The University of Pennsylvania's Department of Obstetrics and Gynecology reflects a long tradition of excellence in clinical and translational research. The Division of Maternal-Fetal Medicine (MFM) and its Maternal and Child Health Research Program (MCHRP) have been key participants in this tradition. In this application, information is provided on the obstetrical service and the proven track record for conducting clinical research at the two hospitals in the University of Pennsylvania Health System (Penn) - the Hospital of the University of Pennsylvania (HUP) and Pennsylvania Hospital (PAH) - which are proposed sites of patient recruitment for this Maternal-Fetal Medicine Units (MFMU) Network application. Each year, approximately 9,000 women are delivered at Penn, and many of these women are documented to be high-risk pregnancies. The obstetric population at Penn also has a diverse racial and ethnic background, which will be an important asset for enrollment in MFMU studies. The proposed MFMU site at Penn will operate within the highly successful MCHRP, which offers continuous enrollment (24/7) into antepartum and intrapartum research studies, outpatient recruitment at all major clinical sites at HUP and PAH, and established protocols for biospecimen collection and databanking. The MCHRP coordinators work closely with coordinators from the Neonatal Research Network at Penn to provide neonatal follow-up. The MCHRP was critical for the successful enrollment of 1,100 women into the nuMoM2b Network study at Penn (U01-HD05088), and the MCHRP is a key asset for the recently designated March of Dimes Center for Prematurity Research at Penn. The investigative team proposed for the MFMU site at Penn has significant experience directing multicenter studies, and each investigator has an exciting research agenda that will add unique perspectives to the MFMU Network. The investigators have a proven track record studying preterm birth; placental biology; genomics, proteomics, and metabolomics; vaginal and gut microbiome; maternal screening for genetic disorders; and models of obstetrical care. The proposed investigators recognize several key specific aims of this application: 1) To aid in the identification of the highest priority issues for research in perinatal medicine; 2) To work within the collaborative environment of the MFMU Network toward the design and implementation of research projects that address high priority issues; 3) To provide the highest quality data for MFMU studies and to provide these data in a timely fashion; and 4) To be involved in the analysis and publication of studies performed by the MFMU Network. The research environment in the Department of Obstetrics and Gynecology at Penn is exciting and continually growing, and the proposed leadership team reflects a strong commitment for full engagement by the department in the MFMU Network. The investigators will be able to leverage the infrastructure of existing programs to develop a successful MFMU site at Penn that meets and/or exceeds all objectives of the four specific aims proposed in this application.